PTAB

IPR2018-00055

Cellco Partnership v. Bridge Post Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method and Apparatus for Tagging Network Traffic Using Extensible Fields in Message Headers
  • Brief Description: The ’747 patent describes a system for tagging network traffic to facilitate targeted advertising without using cookies. The system features a routing device that intercepts a request from a client to a server, extracts non-personal device information (e.g., from the MAC layer), and uses it to generate a persistent, anonymous unique identifier (UID). This UID is combined with other data (instance, location, demographic), encrypted to create a Request ID (RID), and then embedded into an extensible field of the request's HTTP header before being forwarded to the server.

3. Grounds for Unpatentability

Ground I: Claims 10-17 are obvious over Harada, Roker, and Brijesh

  • Prior Art Relied Upon: Harada (WO 00/73876), Roker (WO 2006/081680), and Brijesh (Application # 2006/0265507).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that the combination of these references teaches every element of the challenged claims. Harada was presented as the primary reference, disclosing a system where a proxy server intercepts HTTP requests and augments them with encrypted user profile information (identifiers, demographics, location) inserted into unused HTTP header fields for targeted content delivery. However, Harada did not explicitly disclose using MAC-layer information for the identifier. Roker was argued to supply the motivation for a "static unique identifier" to improve upon existing methods and to obscure the user's identity for privacy. Brijesh was argued to provide the missing element by explicitly teaching the use of a Media Access Control (MAC) address as a persistent device identifier. The combination, therefore, taught a system that intercepts requests and uses a MAC address, obtained during a MAC-layer process, to generate a unique, privacy-preserving identifier that is combined with other user data and embedded in an extensible HTTP header.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references as they all address the same field of endeavor: using a network intermediary to gather user information and modify network requests for targeted content. Petitioner argued a POSITA would have been motivated to improve Harada’s system by incorporating Roker’s teaching of a static, privacy-preserving identifier. Brijesh provided a well-known and predictable solution for implementing Roker’s abstract concept by teaching the specific use of a MAC address as a persistent identifier.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in this combination. The integration involved applying known techniques, such as using a MAC address as an identifier (from Brijesh) and hashing it for privacy (a concept taught by Harada and reinforced by Roker's privacy goals), to Harada's existing framework. This was presented as the predictable combination of familiar elements to yield a more robust and private system.

Ground II: Claims 10-17 are obvious over Harada, Roker, and Candelore

  • Prior Art Relied Upon: Harada (WO 00/73876), Roker (WO 2006/081680), and Candelore (Patent 6,996,238).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented an argument parallel to Ground I, but substituted Candelore for Brijesh as the source for teaching a MAC-based identifier. The core system of intercepting and augmenting HTTP requests was still based on Harada, and the motivation for a static, private identifier came from Roker. Candelore was asserted to be analogous art that teaches using a unique MAC address as a "distinctive device identification" in an IP network to address security and privacy problems. Candelore further disclosed that this MAC-based identifier could be processed through a one-way hash algorithm (SHA-1) to generate a unique key, thus teaching the hashing limitation.
    • Motivation to Combine: The motivation to combine Harada and Roker remained the same. A POSITA would have been motivated to consult Candelore because it addresses the same fundamental problems of device identification and privacy. In light of Roker’s teaching that the specific nature of the identifier is "arbitrary," a POSITA would have looked to known, existing identifiers. Candelore's use of a MAC address was presented as a readily available and suitable option. Substituting Candelore’s specific MAC-based identification method into the Harada/Roker framework was argued to be an obvious design choice.
    • Expectation of Success: The combination would have yielded predictable results. Using a MAC address for identification was a known technique, and Candelore demonstrated its use for security and uniqueness. Applying this known identifier to the system of Harada and Roker would predictably result in a system that identifies users based on their MAC address, which was the intended outcome.

4. Key Technical Contentions

  • Denial of Priority Date: Petitioner argued that the ’747 patent is not entitled to the March 10, 2007 filing date of its provisional application. The petition asserted that the provisional application failed to provide adequate written description support for key limitations that were added later during prosecution to overcome prior art rejections. These limitations included, for example, extracting information during a "Media Access Control (MAC) layer process" and basing the unique identifier on "a MAC address, port identifier, or hardcoded identifier." This argument was central to establishing that several references, including Roker and Brijesh, qualify as prior art.

5. Relief Requested

  • Petitioner requests institution of inter partes review and cancellation of claims 10-17 of the ’747 patent as unpatentable.